diff --git a/includes/class-wc-discounts.php b/includes/class-wc-discounts.php
index fea4eead963..c4e931f6d7f 100644
--- a/includes/class-wc-discounts.php
+++ b/includes/class-wc-discounts.php
@@ -664,6 +664,11 @@ class WC_Discounts {
 	 */
 	protected function validate_coupon_minimum_amount( $coupon ) {
 		$subtotal = wc_remove_number_precision( $this->get_object_subtotal() );
+
+		if ( $this->object->get_prices_include_tax() ) {
+			$subtotal += round( $this->object->get_total_tax(), wc_get_price_decimals() );
+		}
+
 		if ( $coupon->get_minimum_amount() > 0 && apply_filters( 'woocommerce_coupon_validate_minimum_amount', $coupon->get_minimum_amount() > $subtotal, $coupon, $subtotal ) ) {
 			/* translators: %s: coupon minimum amount */
 			throw new Exception( sprintf( __( 'The minimum spend for this coupon is %s.', 'woocommerce' ), wc_price( $coupon->get_minimum_amount() ) ), 108 );